1. Field of the Invention
This invention relates generally to improvements in devices used in the field of wiring and cabling. In particular, the invention relates to devices used in distributing electronic and electrical and hydraulic components, as well as hydraulic lines, through various structures such as aircraft bulkheads. Numerous holes are formed in internal walls or bulkheads of aircraft and in their primary load carrying structural members. Such holes are formed for the purpose of reducing the weight of the aircraft or for the express purpose of permitting electrical cables, hydraulic lines and the like to pass therethrough. The invention is an improvement to devices or apparatus which are connected to the edge of the bulkheads which form the periphery of the hole to prevent wire and tube chafing and to which the electrical cables are attached.
2. Description of the Prior Art
Wire routing devices are well known in the prior art. One of the simplest devices used for this purpose is a plain rubber grommet having a groove in its outer surface for engaging the edge of a bulkhead forming the periphery of a hole. Devices of this type are used to protect the wiring from the sharp edges of the bulkhead and are not used to secure wire cables. Such grommets are commonly found in automobile firewalls.
A split ring grommet or bushing, similar to the automobile type just discussed, is disclosed in U.S. Pat. No. 3,562,847 issued to Jemison on Mar. 4, 1960. Here, the grommet is split so that when in place it has two opposing faces. This facilitates installation of the grommet in the hole.
A bifurcated split ring grommet is disclosed in U.S. Pat. 3,889,909 issued to Koscik on June 17, 1975. A flange and tab are disclosed for engaging a bulkhead edge forming the periphery of a hole. The grommet is adapted to have a single cable attached or secured to it.
There have been various problems associated with the wire routing grommets of the prior art, particularly for aircraft use. It is desirable that routing grommets for aircraft use be easily and simply inserted into the lightening holes of the aircraft prior to the installation of electrical cables, so as to prevent damaging of the insulation on the cables while they are being passed through the holes. Such grommets must provide an abrasion resistant capability so as to prevent degradation of the structural integrity of the cable sheath or wire insulation. It is desirable that a number of cables be attached to a single grommet in a secure manner though as to reduce the number of holes required and to permit optimum placement of the holes which are required. It is highly desirable that the grommet be tightly secured to the bulkhead, particularly in aircraft where vibration is a significant factor and can cause damage to the electrical cables by breaking the protective insulation.